Manufacture of cellulosic product



July 31, 1962 K. J. HARWOOD MANUFACTURE OF CELLULOSIC PRODUCT Filed Feb. 15, 1961 .6 G 0 0 O 0 0 9 0 a linired dtates .i atent 3,046,986 MANUFACTURE F CELLULOSIC PRGDUCT Kenneth J. Harwood, Neenah, Wis, assignor to Kimberly- Clark Corporation, Neenah, Wis., a corporation of Delaware Filed Feb. 15, 1961, Ser. No. 89,399 4 Claims. (Ci. 128-2%) This invention relates to sanitary napkins, and more particularly to improvements in sanitary napkins of the type which are most efiicient when worn in only one direction.

A primary object of the invention is to provide an improved sanitary napkin adapted to be worn, for optimum eiiiciency, in a direction which is clearly indicated by visual examination of the construction thereof.

An important object of the invention is to provide the preferred body contacting side of a highly fluid absorbent portion of a sanitary napkin with improved fluid control and absorbing means presenting an attractive configuration and readily viewable through a gauze-like Wrapper to indicate the proper body contacting side.

Another object is to provide improvements in both the fluid distribution pattern and the fluid absorbing capacity of a sanitary napkin.

Another object is to provide an improved napkin construction which aids in the confinement of fluid migration within a desired central portion of an absorbent pad, thereby resisting fluid transfer to and resultant saturation of marginal portions thereof.

A still further object is to provide an improved sanitary napkin with a body-contacting portion so constructed as to promote rapid fluid strike-through and insure relative dryness of that portion during use.

Other objects and advantages of the improved construction will become apparent to persons skilled in the art upon examination of the description and drawings, Without departing from the scope of the invention as defined in the appended claims.

In the drawings, in which like parts are identified by the same reference numeral,

FIG. 1 is a plan view of a sanitary napkin incorporating the invention,

FIG. 2 is an enlarged partial vertical section taken along line 2-2 of FIG. 1,

FIG. 3 is an enlarged fragmentary plan view of the construction shown in FIG. 2.

FIG. 4 is a fragmentary elevational view of the bottom side of a control element shown in FIG. 3.

As shown cross-sectionally in FIG. 2, a multi-ply sanitary napkin includes various fluid absorbent and fluid control elements maintained in unitary assembly by a gauze-like wrapper 11, enclosing the elements and overlapped in a known manner. The light weight fluid absorbent material of wrapper 11 may consist, for example, of a non-woven webbing or scrim 12 having a very light appliqu 14 of cotton fibers or the like on the exposed side of the wrapper. The present invention is directed to improvements in a multi-ply fluid absorbing element 16 which directly underlies wrapper 11 in c0- operative relation with a contiguous disposed flnif layer 18 directly thereunder.

The various components shown below fluff layer 18 in FIG. 2 are of known construction and form no part of the present invention. The elements shown are in current use in Kotex sanitary napkins manufactured by the Kimberly-Clark Corporation, to whom the present recessed areas therebetween.

' $546,986 Patented July 31, 1962 invention is assigned, and include multiple-ply filler element 20, a fluid spreading baifle 22, a second flufr' layer 24, a springy mat-like control element 25 of long resilient fibers, and a bottom layer 28 similar to element 16 but not embossed as above taught.

The napkin is transversely arced downwardly and longitudinally arced upwardly during use, however the various components remain in the same relative position.

Menstrual exudate is normally deposited on the central portion of the napkin to be aided by gravity in migrating downwardly through the various components. FIGS. 2 and 4 show element 16 comprising 6 to 10 sheets of creped tissue, termed wadding, of a dryer basis 7 weight of about 5 pounds per 2,880 square feet, and a V crepe ratio of about 2.5 or higher, neither the weight nor crepe ratio being critical. Element 16, commonly called the body wadding layer, may alternately comprise upper and lower creped tissue sheets and an intermediate layer or batt of short fiber fluff. The present invention is directed to so modifying either type of body wadding control element as to increase the absorptive rate of exudate therethrough and transfer into batt 18 which may consist of flufi or other fluid absorbent material positioned directly thereunder, while minimizing lateral migration of exudate.

As is well-known in the sanitary napkin art, fluid migrates more rapidly through densified areas of fluid absorbent elements than through areas of lesser density. That general principle is taught by Heitmeyer Patent 1,863,333 assigned to applicants assignee and by other patent teachings. The present concept resides in advantageously employing that principle in a manner both to confine migration of exudate within a central area of element 16 which is a good fluid absorbent element, and to promote migration thereof into a major fluid absorbent element such as fluff element 18.

To eiiect the above result, a central portion of element 16, for example that portion shown at 30, FIG. 1, is deeply embossed in a manner to form well-like depressions 32 therein which extend downwardly through the multiple-ply element to terminate in depending cup-like end closure portions 34. The fibers of the multiple wadding layers are substantially compacted both marginally tions 34. In FIG. 3, depressions 32 are peripherally so indicated while the densified marginal areas are shown FIG. 4 fragmentarily illustrates element 16 inverted to better illustrate the densified cup-like areas 34 which extend downwardly of the main body of element 16 to serve as end closures for depressions 32. Fluids deposited on wrapper 11 .during use readily pass through that fluid permeable element and then may either drop by gravity into depressions 32 or migrate into the nonluid thus deposited in depressions 3?. may first contact either marginal portions of the depressions or the lower end closure portion 34. In any event, such fluid will rapidly migrate, due to the high fiber density in those areas, downwardly to the upper surfaceof fluff batt 18 upon which portions 34 rest. Since a fluff bait, such as element 18, is highly fluid absorbentjfluid transfer between portion 34 and element 18 is rapid.

Fluid deposited in areas intermediate depressions 32 will migrate downwardly to some extent, but due to the known directional characteristics of such a multi-ply element, will migrate laterally to a greater extent than downembossed marginal areas such as 4-2.

soaaese wardly. Lateral migration of fluid is restricted, however, since the migrating fluid soon reaches the densified marginal areas 38 of the depressions from which it rapidly' migrates downwardly to the densified cup-like portions 34 and into batt 18. It is thus seen that regardless of the exact position of fluid deposit, assuming it to be confined within the area provided with depressions 32, lateral migration is arrested by depressions 32 which define localized boundary areas beyond which lateral migration will not extend.

The manner in which element 16 is embossed as shown m'FIG. 2 is known, hence not claimed as novel, per se. Satisfactory embossing may be obtained by mating 7 into the lower major absorbent element 18. When emembossing rolls consisting of a female roll peripherally provided with a plurality of depressions such as bores or the like of controlled .depth for the reception of mating protuberances suchas studs carried by the male roll. The male roll protuberances are of a transverse dimension sufficiently less than the corresponding dimension of the female roll depressions to permit embossing of the multi ple-ply material in the absence of shear stresses of a magnitude to cut the material marginally of the depressions, best shown in FIGS. 2 and 3. The embossing operation results in some compaction of the fibers of the creped sheets comprising element 16 throughout the cum bossed area. As shown in FIG; 2, the total thickness of area, for example, between two spaced depressions, as shown at 40, is of lesser; thickness than are the non- The amount of compaction in the areas such as 49 is, however, substantially less than in either the highly compacted area 38 marginally of the depressions, or in those areas 34 defining the cup-like protuberances. V

. With the napkin assembled as shown in FIG. 2, the lower surfaces of marginal areas 42 rest directly on corresponding areas of element 18, but throughout the centrally embossed area'the lower surfaces of the compacted portions intermediate protuberances 34 are maintained spaced above the corresponding surface of element 18, as shown at 40, by the cup-like protuberances 34 which rest on the upper surface of element 18. It is important that the cup-like protuberances 34' extend sufliciently below the major plane of the bottom intervening surfaces 40 of element 16 to insure that portions 34 serve to space 4 those intervening surfaces sufficiently above the upper surface of element 18, as shown at 40, to prevent fluid transfer therebetween and thus confine such transfer to the densified areas of protuberances 34. While neither the magnitude nor configuration of the embossed central area is critical, it is preferred that such area does not dimensionally exceed more than about 70%80% of the total surface area of the various registered elements comprising the pad portion of the napkin, thus insuring that the pad margins will remain dry during use.

While protuberances 34 have been shown and described as comprising closed cup-like areas, certain adjustmentsfof the embossing rolls may result in the fibers being torn apart at the lower ends thereof as viewed in FIG. 2. The closed cup-like protuberances 34 are produced by a roll adjustment which providesdesired clearance between'the stud ends and the bottom of the bores in the female roll. With less clearance therebetween the ends of the protuberances may undergo rupture which maybe permitted as above mentioned. Some such aperturing of the protuberances has been found permissible Without detriment to the above described rapid fluid migrationpaths between elements 16 and 18. I

, While the invention has been above described in respect to an element 16 comprising plural sheets of creped tissue only, the concepts herein taught may be employed in a control element wherein those tissue plies shown intermediate the top and bottom creped wadding layers, FIG. 2, are replaced with a single layer of short fiber flufl. The element of such alternate assembly is deeply embossed in the manner above taught to gain the same bossed as above taught, a control element of such alternate construction assumes the same general configuration and functions in the same manner as does the multi-ply sheet element shown in FIGS. 2 and 4, the central portion of which consists of plural sheets of creped tissue instead of a central layer or batt of fluff. Fluid deposited centrally thereof, while having the same tendency to migrate in a transverse rather than in a downward directionas above mentioned, is in like manner directed downwardly by the densified marginal areas and through the depending cup-shaped areas for rapid transfer into element 18.

I claim:

l. A sanitary napkinhaving incombination, a plurality of layers of fluid. absorbent and fluid control elements, a fluid pervious Wrapper enclosing and maintaining said elements in unitary assembly, one of said fluid absorbent elements being positioned contiguously of said wrapper and comprising multiple plies of creped sheets of fibrous material, said multiple-ply element being provided throughout an area spaced inwardly of the margins thereof with a plurality of spaced-apart chamber-like depressions leading from the wrapper side of said element to extend therethrough and terminate at the opposite side of said element in outwardly projecting cup-like portions, the fibers of said multiple sheets being substantially densified in areas marginally of said depressions and throughout said cup-like portions, and a second fluid absorbent element in contiguous engagement with the cup-like portions of said multiple-ply element for fluid transfer therebetween. i

2. The device of claim 1 wherein said depressions are of generally cylindrical configuration and said cup-like portions are of generally semi-spherical configuration. V 3. A sanitary napkin having in combination, from the top down as positioned during use, a fluid pervious bodys contacting wrapper, a fluid absorbent and control element positioned immediately thereunder, said fluid control element consisting of about 6 to 10 sheets of light weight creped paper, said control element having a centrally disposed portion deeply embossed to define a plurality of spaced-apart depressions leading from the wrapper contacting surface thereof downwardly throughsaid element and terminating in substantially closed ,protuberances positioned below the major plane of the bottom surface thereof with the fibers of said multiple sheets substantially densified into a common mass within areas marginally defining said depressions and associated protuberances,

and a major fluid absorbing element of fiber density less than the density of the depression-defining margins of said control element positioned below said fluid control element in supporting engagement with the protuberances of said control element for rapid fluid transfer therebe tweeu. t

4. A sanitary napkin having in combination, from the top down as positioned during use, a fluid pervious body contacting wrapper, a fluid absorbent control element positioned immediate thereunder, said fluid control element consisting of upper and lower sheets of light weight creped paper and an intermediate layer or batt of short fibers in the form of fluif, said control element having a. cent-rally disposed portion deeply embossed to define a plurality of spaced-apart depressions leading from the wrapper contacting surface thereof downwardly through said element and terminating in substantially closed protuberances positioned below the major plane of. the botstantially densified into a common mass within areas marginally defining said depressions and throughout said associated protuberances, and a major fluid control element of fiber density less than the density of the depression-defining margins of said cont-r01 element positioned below said fluid control element in supporting engagement with the protuberances of said control element for rapid fluid transfer therebetween.

References Cited in the file of this patent UNITED STATES PATENTS Morin Apr. 9, 1957 Burgeni Sept. 13, 1960 FOREIGN PATENTS Belgium Apr. 15, 1955 

